Refactor asap_add_code_coverage_all_targets to add standard excluded directories by default

[abdes]

Rather than exclude patterns such as test files, system includes, and third party dependencies added by CPM in the master CMakeLists.txt, these standard excludes should be automatically added.

  function(asap_add_code_coverage_all_targets)
    # Add standard exclusion patterns for code coverage reports
    if("${CMAKE_C_COMPILER_ID}" MATCHES "(Apple)?[Cc]lang")
      # For clang we'll be using llvm-cov which expect regex as input for
      # exclusions
      set(STANDARD_EXCLUDES '.*/test/.*' '.*/\.cache/CPM/.*' '/usr/.*')
    else()
      # For GNU however, we'll be using lcov which expects file patterns as
      # input for excludions
      set(STANDARD_EXCLUDES */test/* */.cache/CPM/* /usr/*)
    endif()
    add_code_coverage_all_targets(EXCLUDE ${STANDARD_EXCLUDES} ${ARGV})
  endfunction()